evolve: use repo.setparents() instead of repo.dirstate.setparents() setparents() was added to localrepository class in 2012, and now we finally have some differences between calling repo.setparents() vs repo.dirstate.setparents(): _quick_access_* things, introduced in hg 5.3. This patch fixes an actual quick-access desync problem where repo[b'.'] would be different from repo.dirstate.p1(), as demonstrated by test-evolve-phase-divergence.t when ran on hg 5.3rc0 and later. Modified _uncommitdirstate() too, because it is used in dirstatedance(), which sometimes follows repo.setparents() calls.

tests: demonstrate that evolve swaps parents of merge commits Tests currently pass, don't forget to change FIXME items.

ci: cache pytype-related files between runs